Once Upon a Time cast photo

The special two-hour “Once Upon a Time” on Sunday (Nov. 15) starts off with the regular Storybrooke crew dealing with Dark Swan (Jennifer Morrison) and the events that took place in Camelot. This whole arc presents a lot of obstacles for the fan-favorite couples, and creators Adam Horowitz and Edward Kitsis tell Zap2it that the relationship roller coaster is something that won’t stop until the series does — though they do know what the series finale looks like.

“No relationship is smooth sailing and if it is, it certainly doesn’t belong on TV because it’s boring,” says Kitsis with a laugh. “What we have is complicated relationships between three different couples and we’re going to see those play out.”

“We know that Emma and Hook right now have some complications as he’s trying to save her. Robin and Regina are very much in love, but they have to deal with the Zelena of it all. And Rumpel is trying to become a better person, but Belle has been scorned one too many times,” Kitsis continues. “Those are on-going relationships for the series, so they are not arc dependent. We don’t try to wrap them up the way we do with ‘Frozen’ or Camelot or things like that.”

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The executive producers also say that they basically know where all these characters are going to eventually end up — but they aren’t telling.

“We do have [the ending] in our heads. We will not share it,” says Horowitz. “When we started the show, we had this idea at the very start and although we get people coming in and out — over the years things have evolved — but that core idea remains and it has solidified itself as we move forward. We’re excited to one day build toward it. … This is a show about love and hope, and we are going to see these couples fight for their happy endings.”

To this, Kitsis quips, “Everybody dies and we learn that a show about hope ends with you having no hope. That’s the twist no one saw coming. The show is actually going to end in the bleakest, darkest way possible: with everyone dying.”

He’s just kidding, “OUAT” fans.

Tune in Sunday, Nov. 15 at 8 p.m. ET/PT on ABC for the special two-hour broadcast, “Birth” and “The Bear King.” Watch a preview of the episode below.